This invention has as objects to provide new oil-soluble dispersing compositions, a process for the manufacture thereof, and lubricants containing said compositions. More particularly, this invention relates to new oil soluble dispersing compositions produced by reacting a substituted succinic anhydride with hexamethylene tetramine and an alkyl phenol.
One of the main problems now encountered in engine lubricants is due to the unavoidable presence in the lubricant of extraneous particles in suspension, such as carbonaceous substances and sludges emanating from soots, from products of fuel and lubricant deterioration, and from water.
The accumulation of these suspended substances seriously affects the lubricant efficiency in the engine and it is thus important to prevent the agglomeration and the deposition of these undesirable substances, as varnishes, hard carbonaceous materials and sludges, in the different parts of the engine. For several years, attempts have been made to cope with these difficulties by using organo-metallic additives, such as, for example, sulfonates, phenates or salicylates of alkaline-earth metals, or organic additives such as, for example, polymethacrylates, either grafted or copolymerized with nitrogenous unsaturated reactants, or succinimides of polyethylene-polyamines.
However, the use of organo-metallic additives is limited by the likelihood of deposition of various metal oxides onto the electrodes of the sparkplugs in spark-ignition engines; the resultant deposits may cause pre-ignition which is detrimental to the engine. The known ashless organic additives suffer from the disadvantage of a limited efficiency at high temperature.
Thus, the French patent application FR No. 2 264 084 discloses detergent additives for lubricating oils which may be obtained by reacting hexamethylene tetramine with an alkylphenol having at least one of the positions 2, 4 and 6 of the aromatic ring unsubstituted.
The U.S. Pat. No. 3,962,104 discloses ashless detergent additives for lubricants consisting of quaternary ammonium salts, formed by the reaction of a tertiary amine (e.g. hexamethylene tetramine) with an olefin oxide in the presence of an excess of water, followed by the reaction with an organic acid compound which may be, for example, a substituted succinic anhydrice (dodecenyl-succinic anhydride or polyisobutenylsuccinic anhydride) or an alkylphenol.